RE: Struggling with holding low
All good advice. I had a very similar issue a while back but I was just the opposite. I was holding above and not able to bring it down.
The best thing I did was practive holding the pin on the target without shooting an arrow. Draw, hold for about 5-10 seconds, and then let down. Make sure you place your finger on the trigger as well, as if you have full intention on shooting the arrow. Do this for anywhere between 5-10 times and then shoot one arrow. Then do the whole thing over again.
It worked for me.